Internet Protocol (IP) communications from one subscriber's terminal to another subscriber's terminal is known. In IP based communications over an IP network, IP services are provided to subscribers. When the subscriber's terminals are multimedia terminals, e.g. multimedia phones, such IP services e.g. relate to multimedia components provided as enhancement for voice over IP communication. It is known to enhance a voice call with one or more multimedia components, such as video sharing, still picture sharing, music sharing, calendar sharing, file transfer etc. This is sometimes referred to as ‘Enriched communication’. These multimedia components in the call are facilitated through an IP session, e.g. based on an IP Multimedia Subsystems (IMS) network. Calling party and called party may during establishment of the call exchange their respective capability for such IP based multimedia enhancement to the call. This capability includes, among others, an IP address to be used for the communication.
It is observed that with the prior art it is not possible to request the execution of an Internet Protocol (IP) service application of a subscriber's multimedia terminal, such as an IP Multimedia Subsystem (IMS) terminal, outside the context of an existing IP communication session (e.g. voice call).
The only exception in the prior art is formed by Session Initiation Protocol (SIP) based services. The SIP terminal deposits its contact address, viz. IP address, at a registrar, in an IMS network formed by a Serving Call Session Control Function (S-CSCF) entity. This IP address is used for establishing a SIP session. The terminal hence executes a SIP service application, in the sense that it can receive an initial SIP transaction. Receiving the initial SIP transaction constitutes a request for the execution of an IP service, such as establishing a communication session or accepting an Instant message.
Besides SIP based communication services, there is no general mechanism for a subscriber's multimedia terminal, such as an IMS terminal, to offer IP based communication services such as a hypertext transfer protocol (HTTP) service, a Mail server, or a File Transfer Protocol (FTP) service.